THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

JAKE TAPPER, CNN ANCHOR: It's going to be a great debate. A reminder: tonight's Clinton-Sanders debate in Brooklyn. Starts at 9 p.m. Eastern right here on CNN. That's 6 p.m. for all you folks in California, Washington and Oregon. That's it for THE LEAD. I'm Jake Tapper, turning it over to Wolf Blitzer in THE SITUATION ROOM. Mr. Blitzer, take it away.

[17:00:21] WOLF BLITZER, CNN ANCHOR: Happening now, breaking news showdown. Hillary Clinton versus Bernie Sanders. Tonight's CNN presidential debate is the final face-off before the absolutely crucial New York primary. He has the momentum; she has the math. The stakes are high, and the stage is set.

Fight for New York. He was born here. She was elected here. Sanders has proved he can draw big crowds in New York, but Clinton leads in the polls. Can tonight's debate determine who wins most of the state's 247 delegates?

Bern moment. Since Hillary Clinton swept the early voting south, Bernie Sanders complains the election calendar, quote, "distorts reality," while his wife tells CNN the process isn't democratic at all. Is this Sanders's last chance to break through Hillary Clinton's firewall?

And no charges. A sigh of relief for Donald Trump's campaign as his campaign manager won't be prosecuted for grabbing a reporter. While all three Republican candidates will appear at a GOP gala in Manhattan across the river from our Democratic debate.

BLITZER: The breaking news: the battle of Brooklyn now just four hours away. We're live from the Brooklyn Navy Yard in New York, where Hillary Clinton and Bernie Sanders will face off in tonight's critical Democratic presidential debate on CNN.

It's the final showdown before Tuesday's New York primary. Sanders still carries the accent of his Brooklyn youth. Hillary Clinton's campaign is headquartered here. The stakes clearly are enormous.

A Clinton victory could break Sanders's recent momentum and put the nomination within her grasp. A Sanders win in the state Clinton represented as the U.S. senator could shake her campaign to its core. Amid the rhetoric and big rallies, the race has been getting nasty as the two sides hammer one another on policy and qualifications. Will tonight's showdown boil down to insults or issues?

And the insults are flying among Republican candidates. All three will appear tonight at a black-tie GOP gala. Ted Cruz, accusing Donald Trump's campaign of threatening violence even as prosecutors decide not to charge Trump's campaign manager for grabbing a reporter. I'll speak with Clinton campaign press secretary, Brian Fallon. And our correspondents, analysts and guests, they will have full coverage of all the day's top stories.

Let's begin with our senior Washington correspondent, Joe Johns. Joe, some hard feelings going into this debate. Set the stage: what's the latest?

JOE JOHNS, CNN SENIOR WASHINGTON CORRESPONDENT: That's true, Wolf. Quite frankly, here in New York and across the state, it's been a week of acrimony, sometimes rivaling the Republicans, a tone of bitterness right up until last night. It shows how much Bernie Sanders wants to change the dynamic here in New York and what the Clinton campaign will do to stop him.

(BEGIN VIDEOTAPE)

JOHNS (voice-over): Tonight the battle lines are drawn.

SEN. BERNIE (D-VT), PRESIDENTIAL CANDIDATE: You elect me president, you're going to have a president who is prepared to take on the billionaire class, not take their money.

JOHNS: Sanders speaking today to Reverend Al Sharpton's National Action Network, the same group Clinton addressed a day earlier, appealing to African-American voters in New York.

B. SANDERS: We are going to invest in education and jobs for our kids, not jails and incarceration.

JOHNS: Sanders also holding a rally with thousands of supporters last night in Lower Manhattan.

B. SANDERS: When I look at an unbelievable crowd like this, I believe I'm going to win here in New York next Tuesday.

JOHNS: But he wound up having to do some cleanup after one of his supporters made this comment on stage.

DR. PAUL SONG, HEALTH CARE ACTIVIST: Medicare for all will never happen if we continue to elect corporate Democratic whores who are beholden to big pharma.

JOHNS: Dr. Paul Song, a health care activist and the husband of CNN's Lisa Ling, later apologizing on Twitter, saying it was insensitive, and Sanders disavowing the comments, tweeting, "There's no room for language like that in our political discourse." The Clinton campaign firing back on CNN. UNIDENTIFIED MALE: I'm glad that Senator Sanders finally decided to

disavow it. I think what's troubling overall has been his campaign strategy in New York to launch these kinds of personal attacks Hillary.

JOHNS: While Sanders filled Washington Square Park, Clinton was holding a much smaller rally in the Bronx.

[17:05:06] Vote not just for me. My name will be on the ballot. But vote for yourselves. Vote for your families. Vote for your children, your grandchildren. Vote for the future of the Bronx.

JOHNS: And turning her focus once again to the Republicans.

CLINTON: One of them denigrates New York values. One of them, Mr. Trump, wants to set Americans against each other.

JOHNS: And as the Democratic fight reaches a critical moment, Sanders is complaining that the primary process has made his path to the nomination more challenging.

B. SANDERS: There are people that say why does Iowa go first? Why does New Hampshire go first? But I think that having so many southern states go first kind of distorts reality, as well.

JOHNS: Sanders wife, Jane, echoing that point today on CNN.

JANE SANDERS, BERNIE SANDERS' WIFE: I think it is designed badly. I don't like the fact -- I don't think it's rigged. I don't think it's designed in anybody's favor. I just don't think it's very democratic.

(END VIDEOTAPE)

JOHNS: Though Hillary Clinton has led by double digits in the polls here in New York for weeks, campaign aides for Clinton are seeking to lower expectations about what the final vote margins will be. They are fully aware of Bernie Sanders' unique ability to close late in the race, Wolf.

BLITZER: All right, Joe, thanks very much. Joe Johns reporting.

As Bernie Sanders and Hillary Clinton make their final preparations for tonight's debate, let turn to our senior Washington correspondent, Jeff Zeleny.

Jeff, what's the latest from the two campaigns? Specifically, what do we know about what they'll be looking for tonight?

JEFF ZELENY, CNN SENIOR WASHINGTON CORRESPONDENT: Well, Wolf, this is debate No. 9, but it's certainly a different moment in time in this race, largely because the calendar is moving so much forward here. We are near the end of this. That's why it is such an important moment here.

A couple of things to look for: judgment versus tested. Senator Sanders is going to be raising questions specifically about the judgment of Secretary Clinton. Going through all of those votes that she has taken, you know, from the Iraq War to other things.

But at the same time, she'll be raising new and tougher questions about "Is he tested? Can he handle the job as president." Really asking some questions about his qualifications.

Now, moving on, location always matters in politics. It's location, location, location. Tonight New York actually does matter. The issues of this state will be front and center in this race, from fracking upstate to Wall Street, of course, to income inequality.

But Senator Sanders has been trying to sort of move beyond his attacks just on Wall Street. Because Wolf, a lot of people here in New York make their living on Wall Street. So he's trying to broaden that out a little bit. So watch for how those Wall Street attacks actually play tonight.

And finally, Sanders' growth. Does he have growth appeal tonight? One of his biggest challenges that he's trying to do is expand his support level and really bring in some of those people who aren't quite sure about him. They might like what he -- what he says but aren't sure if he can actually be elected, really try and bring those people home here in New York.

Wolf, he knows this is his best shot here, politically speaking, to up-end this race. If he doesn't win next week, it's very hard for him mathematically to do that with all the delegate lead that she has -- Wolf.

That's a fair point. All right. Jeff Zeleny, thanks very much.

Joining us now is Hillary Clinton campaign press secretary Brian Fallon. Brian, thanks very much for joining us.

BLITZER: He apparently had some trouble in that "New York Daily News" editorial board interview, Bernie Sanders getting specifics on some of his core issues. I assume he's prepared. He's coming in with a lot of specifics tonight. What's going to be her strategy?

FALLON: Well, I think that we want to tell the story that that "New York Daily News" editorial board interview revealed, and it's really the core argument that we've been making in this primary all along, which is that Hillary Clinton is the one who has studied on the details. She has the specifics to go along with her plans. She can tell you exactly how she's going to go about pursuing change as president. She can tell you how she's going to deliver and get results. That's how you can trust her to deliver on the job that she says that she's going to perform.

BLITZER: Don't you think he'll have specific answers tonight? Because he -- I assume he assumes -- he knows he's going to be asked a lot of specific questions.

FALLON: Well, we've seen in all the debates up till now some unstable performances from Senator Sanders, especially when it comes to details on foreign policy, how he's going to combat ISIS. And that has been a lingering problem for him. He doesn't veer off his stump speech in many of these debate appearances. And I think that that "Daily News" interview really shone a spotlight on that soundbite style approach.

In New York, the scrutiny here is much tougher; the spotlight shines brighter. I think that that's now been exposed these last few days, and that, combined with the increasingly negative tone from his campaign, explains why Hillary Clinton's lead here has proven to be a lot more durable than people expected.

BLITZER: But he is getting these huge crowds of young supporters, a lot of young -- yesterday at Washington Square Park, thousands and thousands of people. He's getting -- he's getting bigger crowds than Hillary Clinton is. How do you explain that?

[17:10:06] FALLON: Well, he had a great outpouring of support at that rally last night.

You know, it is a very good thing for our party, the enthusiasm that his campaign is generating. It's a credit to the campaign that he is running, that he is inspiring so many young people especially. And so we tip our cap to him on that. I do think that what matters most in terms of the numbers is not crowd size, but who turns out to vote.

And when you accumulate all the results of the primaries that have happened so far, Hillary Clinton's lead among the voters, the electorate that has shown up at all of these primaries is more than 2.4 million people over Senator Sanders. That's how many more votes that she's collected.

She leads in the popular vote. She leads in the pledged delegate total. She's won my states. By every measure, she is ahead. And that's why I think New York now is a -- this has been a marathon. New York is a critical mile marker. If he doesn't catch up to her at this point, it's hard to see where that's going to happen.

BLITZER: But if there is this enthusiasm gap among younger people, what is she going to need to do to shrink that gap?

FALLON: Well, this is something that we've been working on consistently. She has said, even if they're not for her now, she's always going to be them.

I think we have proposals that, over time, young people will gravitate towards, especially when it comes to making college more affordable, letting people refinance their loans at lower interest rates. So we're going to continue to tell that story.

And then, looking ahead to a general election, once this nomination process concludes, when the two campaigns come together with the stakes being so high, I think all of the polls that show potential general election matchups show that those young people come home and support the Democratic nominee against Donald Trump or Ted Cruz.

BLITZER: And you're convinced, if she gets the nomination, Bernie Sanders and his supporters will be there for her? They'll actively go ahead, raise money, get out there and generate support? Are you confident of that?

FALLON: We're hopeful, Wolf. That is what Hillary Clinton did in 2008 after a very spirited contest between her and Barack Obama. She not only endorsed him, gave a stirring convention speech, went out and campaigned for him, urged all of her supporters to support him in the general election. We're hopeful that that's what Senator Sanders will do, too. I think that the tone that we've heard from him in the last week or so only impairs that. So hopefully, we can get back to the issues.

BLITZER: You're hopeful but not confident. Is that what I'm hearing?

FALLON: I think that it is the responsibility of the candidates to conduct their campaigns in these closing weeks in a way that does not inhibit the unity that we will need to pursue when this nomination fight is over.

BLITZER: I've noticed in recent days she's really pivoted a lot; and she's going after Donald Trump and Ted Cruz, looking ahead, potentially, to a general election. Are we going to hear more of that tonight, you think?

FALLON: I wouldn't be surprised if you heard Donald Trump's name past her lips this evening. You're right that she has been talking about Donald Trump and Ted Cruz, calling them out on some of their more outrageous statements and positions.

Wolf, that is not her looking past this primary. That is a very deliberate strategy in terms of how we appeal to Democratic primary voters here in New York and in the states that are still left to vote. We believe that it is an important front-of-mind consideration for Democratic primary voters to think about who is the tested candidate that can go up against either Donald Trump or Ted Cruz in a general election.

So that is -- that is a direct appeal to Democratic primary voters even as we make those arguments.

BLITZER: Listen to what Senator Sanders said last night on "The Larry Wilmore Show" when he asked Senator Sanders if the system, the Democratic system was rigged. Listen to this.

(BEGIN VIDEO CLIP)

B. SANDERS: One can argue, people say why does Iowa go first? Why does New Hampshire go first?

LARRY WILMORE, HOST, "THE LARRY WILMORE SHOW": Yes.

B. SANDERS: But I think that having so many southern states go first kind of distorts reality, as well.

(END VIDEO CLIP) BLITZER: Just a reminder. She won all those southern contests, basically, because she had enormous support in the African-American community. He doesn't like that. Your reaction.

FALLON: Well, a few quick points. No. 1, if you think of two of the earliest states that go in this process, one is Iowa. The other is Nevada. Both of them are caucuses. Most of the success Senator Sanders has had to date in this contest have been caucuses. So we outperformed him in the format where he is best suited to compete and win in those two states that are at the front of the calendar. That's No. 1.

No. 2, I don't think states like Massachusetts and Ohio, states where we racked up important victories, where he contested in fully, count as southern states.

And thirdly, I'm not sure even what point he's making when he suggests that there has been too many, quote unquote, "southern states" at the front of the calendar. States like Florida, states like Texas, these are very diverse states that are a true test of your appeal to a diverse electorate.

And so I'm not sure if Senator Sanders is making some kind of commentary that's based on his inability to appeal to diverse electorates in some of those states that voted earlier in the calendar. I think he needs to explain himself a little bit more than what we heard in that sound bite.

BLITZER: And the -- and she won those states, Florida and Texas. That's the point you're trying to make.

FALLON: Right. Because -- and she's proven time again that her appeal is very broad in terms of the broad-based winning coalition that we've been able to put together over the course of this primary calendar. What you've seen from Senator Sanders is an inability to compete in the biggest, most diverse states. That's why a state like New York and California, it's so hard to believe that he's going to mount a comeback there.

[17:15:13] BLITZER: Brian, I want you to stay with us. We are here at the Duggal Greenhouse at the Brooklyn Navy Yard.

Much more coming up. We're going to continue this conversation. Lots of news happening. We're getting ready for the Democratic presidential debate right here in Brooklyn. Much more after this.

(COMMERCIAL BREAK)

BLITZER: We're counting down to tonight's crucial Democratic debate right here in Brooklyn. We're at the Duggal Greenhouse. We're waiting for the debate to start. We're back, in the meantime, with Clinton campaign press secretary Brian Fallon.

Lovely setting, by the way, isn't it? They have really done an amazing job.

FALLON: CNN has done a great job putting this together.

BLITZER: They're getting ready.

Let's talk about an ugly incident that occurred. A Sanders supporter, we heard it earlier, Dr. Paul Song who happens to be married to Lisa Ling, one of our CNN reporters, used the term "corporate Democratic whores" just a little bit after mentioning -- criticizing Hillary Clinton at a rally for Bernie Sanders last night at Washington Square Park. He disavowed it later. He apologized for that.

And Bernie Sanders issues a statement saying Dr. Song's comment was inappropriate and insensitive. There's no room for language like that in our political discourse. Do you accept that tweet, that apology?

FALLON: Yes. It was clearly an insensitive comment, but the gentleman apologized, the Sanders campaign disavowed it this morning. So I don't think we will dwell on that incident.

I just think, in general, it's a reminder that both campaigns need to be mindful of the tone that they set in terms of what the candidates are saying, because surrogates take their cues from the candidates. And increasingly the Sanders campaign and Senator Sanders himself has gotten increasingly nasty and personal with respect to the rhetoric that he's using on the stump. And I think that that has had a trickledown effect to some of the surrogates.

We'd like to see the level of the discourse elevated across the board.

BLITZER: You're ready to move on from that?

FALLON: Yes.

BLITZER: As you know, the secretary, I'm sure, would have loved to have had this whole thing wrapped up by now, but do you believe that she can wrap up the pledged delegate count, the necessary number of delegates she will need by the end of this month, next month, California? When do you think she'll have that? Forget about the super delegates for now.

FALLON: Sure. And all along we have been stressing our lead with respect to the pledged delegates. Because I think the appropriate role of super delegates is to really come in at the end and ratify the choice that has emerged through the primaries and caucuses in terms of who leads among the pledged delegates.

And so what we have found is that, as of now, we have a lead, significant lead of about 220 or so pledged delegates, which already far exceeds the largest lead that then-Senator Obama ever had over Hillary Clinton in 2008. And we expect to build on that lead here in New York next Tuesday. We expect to further add to that lead with the five states that vote on April 26.

As a result of the outcomes in these six states that are coming up, I think that, by the end of the month of April, we'll be somewhere in the neighborhood of 90 percent of the way towards the necessary threshold to gain the nomination. I think that Senator Sanders' climb is very steep right now. And if

it's going to begin anywhere, it pretty much needs to begin here in New York. I've seen the Sanders campaign down-talk the significance of the New York primary. That contradicts the narrative that they've been spinning out there for the last several weeks where they were encouraging people to look ahead to New York as the place where they were going to make their stand.

BLITZER: Yes, but that's -- if he upsets Hillary Clinton in New York next Tuesday, that would be a huge moment.

FALLON: Well, they have all along been trying to tell a story that is very much based on momentum. But at some point they need to tell a story that's based on math. And to be honest, even a victory here, a small victory for the Sanders campaign, would not fundamentally alter the math. They need to not just win, but win big. They need to start winning with 60 percent of the delegates in each of these big states.

BLITZER: But psychologically, a win would be significant.

FALLON: Well, we think we're going to win. And when we do win next week, it will further set him back. It will make clear, I think, that he is not going to be able to erase this deficit that he faces in the delegate count. Hillary Clinton, I think, it will be clear by the end of April, that she will have a pledged delegate lead that cannot be overtaken, irrespective of the super delegates. And the prospect of an open convention, I think that that is never going to happen. It's -- there's a zero percent chance to that. She's going to have an insurmountable pledged delegate lead and, as a result of that, be able to clinch the nomination well before the convention.

BLITZER: Brian Fallon, thanks very much for joining us.

FALLON: Thanks, Wolf.

BLITZER: Brian Fallon from the Hillary Clinton campaign.

By the way, coming up, I'll also be speaking with a top Bernie Sanders supporter, the former NAACP president, Ben Jealous. He'll be joining me here, as well, at the Brooklyn Navy Yard, the Duggal Greenhouse. Much more coming up. Our coverage continues right after this.

(COMMERCIAL BREAK)

[17:29:01] BLITZER: We're just a few hours away from the CNN Democratic presidential debate. You're looking at live pictures from inside the Duggal Greenhouse here at the Brooklyn Navy Yard, getting ready for this historic, critically important presidential debate in New York.

Do you know, Gloria, Senator Sanders seemed to stumble a little bit in that interview in the "New York Daily News"...

GLORIA BORGER, CNN CHIEF POLITICAL ANALYST: A little?

BLITZER: How important will it be for him to get into specifics tonight?

BORGER: I think it's going to be very important, because you'll press him and Hillary Clinton will press him on specifics. Because, you know, she says that he's not experienced enough to be president of the United States, that he hasn't put meat on the bones when it comes to his -- his policy development.

I think that's what we saw in that -- in that "Daily News" interview. And I think she's going to continue to go after him on that to make the case that she actually has the credibility on policy to become president of the United States.